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From:   Anton Vasilyev <vasilyev@ispras.ru>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Anton Vasilyev <vasilyev@ispras.ru>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        Gaurav Pathak <gauravpathak129@gmail.com>,
        Hannes Reinecke <hare@suse.de>,
        Sinan Kaya <okaya@codeaurora.org>, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org
Subject: [PATCH] staging: rts5208: add check on NULL before dereference
Date:   Sat,  9 Jun 2018 19:38:29 +0300
Message-Id: <20180609163829.30619-1-vasilyev@ispras.ru>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

If rtsx_probe fails to allocate dev->chip, then NULL pointer
dereference occurs at rtsx_release_resources().

Patch adds checks chip on NULL before its dereference at
rtsx_release_resources and passing with dereference inside
rtsx_release_chip.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
---
 drivers/staging/rts5208/rtsx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rts5208/rtsx.c b/drivers/staging/rts5208/rtsx.c
index 70e0b8623110..952dd0d580cf 100644
--- a/drivers/staging/rts5208/rtsx.c
+++ b/drivers/staging/rts5208/rtsx.c
@@ -623,12 +623,13 @@ static void rtsx_release_resources(struct rtsx_dev *dev)
 
 	if (dev->irq > 0)
 		free_irq(dev->irq, (void *)dev);
-	if (dev->chip->msi_en)
+	if (dev->chip && dev->chip->msi_en)
 		pci_disable_msi(dev->pci);
 	if (dev->remap_addr)
 		iounmap(dev->remap_addr);
+	if (dev->chip)
+		rtsx_release_chip(dev->chip);
 
-	rtsx_release_chip(dev->chip);
 	kfree(dev->chip);
 }
 
-- 
2.17.1